Why Are My GCP Log Entries Missing When Logging from a Containerized .NET Core Backend Service?

I have a .NET Core backend service (not a web app) running in a container on a VM, and I'm using the Google.Cloud.Logging.V2 library to send logs to GCP Logging. However, while I see output from Console.WriteLine, the log entries never appear in GCP Logging.

I created the VM with --metadata="google-logging-enabled=true" and am using the following logger implementation:

CSHARPCopied
using Google.Api;
using Google.Cloud.Logging.Type;
using Google.Cloud.Logging.V2;

public interface ILogger<TType>
{
    void Log(LogSeverity severity, string message, IDictionary<string, string>? labels = null);
}

public class Logger<TType> : ILogger<TType>
{
    private const string ProjectId = "myproject";

    private readonly LoggingServiceV2Client _client = LoggingServiceV2Client.Create();
    private readonly LogName _logName = new(ProjectId, typeof(TType).FullName);

    private readonly MonitoredResource _resource = new MonitoredResource()
    {
        Type = "gce_instance"
    };

    public void Log(LogSeverity severity, string message, IDictionary<string, string>? labels = null)
    {
        string messageId = DateTime.Now.Millisecond.ToString();
        string entrySeverity = severity.ToString().ToUpper();

        var logEntry = new LogEntry()
        {
            LogNameAsLogName = this._logName,
            Severity = severity,
            TextPayload = $"{messageId} {entrySeverity} {typeof(TType).Namespace} - {message}"
        };

        // Add log entry to collection for writing. Multiple log entries can be added.
        IEnumerable<LogEntry> logEntries = [logEntry];
        this._client.WriteLogEntries(this._logName, this._resource, labels, logEntries);
    }
}

For example, I invoke the logger as follows:

CSHARPCopied
string message = $"Worker running at: {DateTimeOffset.Now}";
logger.Log(LogSeverity.Warning, message);
Console.WriteLine(message);

The service account running the container has the following roles:

• Artifact Registry Reader
• Logs Writer
• Monitoring Metric Writer
• Storage Object Viewer

I want the logs to include proper severity, labels, and metadata, but they aren’t appearing in GCP Logging. What could be causing this issue?